Quantitative analysis of apoptosis-related gene expression in hepatocellular carcinoma.

BACKGROUND

The suppression of apoptosis is an important factor in tumor progression in hepatocellular carcinoma (HCC). However, to the authors knowledge the clinicopathologic importance of the expression of apoptosis-related genes (bcl-2, bax, and survivin) in HCC remains unclear. In the current study, the authors investigated the correlation between expression of apoptosis-related genes and the occurrence of spontaneous apoptosis in HCC. In addition, the prognostic significance of the expression of apoptosis-related genes in patients with HCC was analyzed.

METHODS

Tissue samples were obtained through surgical resection of the liver in 53 patients with HCC and 5 patients without HCC. The expression levels of bcl-2, bax, survivin, and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA were analyzed using real-time reverse transcriptase-polymerase chain reaction (RT-PCR). The bcl-2/bax ratio and survivin/GAPDH ratio of the tumors were compared with clinicopathologic findings. In addition, apoptotic tumor cells and the proliferative activity of tumor cells were detected using immunohistochemistry.

RESULTS

The bcl-2/bax ratios of the tumors were not different from those of noncancerous liver tissue samples obtained from regions distant from the tumors and were not found to correlate with apoptosis or with clinical importance in HCC. In contrast, the survivin/GAPDH ratios of the tumors were significantly higher than those of noncancerous liver tissue and demonstrated a negative correlation with apoptosis and a positive correlation with the proliferative activity of tumor cells. Moreover, patients who had tumors with a high survivin/GAPDH ratio were found to have a high incidence of disease recurrence.

CONCLUSIONS

The real-time RT-PCR method appears to be a useful technique with which to detect reliable gene expression in tissues, and the detection of survivin mRNA expression by this method may be a useful marker for identifying patients with HCC who have a high risk of disease recurrence.